Telegraph exchange system



Sept. 19, 1933. s, VERNAM TELEGRAPH EXCHANGE SYSTEM Filed May 21, 1931 INVENTOR GILBERT s. VERNAM BY ATTORNEY Patented Sept. 19, 1933' TELEGRAPH EXCHANGE sYs'rnM',

Gilbert S. Vernam,,Hackensack, N. 1., assignor Q. I

to International Communications Laboratories, Y r

Inc., New York, N. Y.,

7 York Application My invention relates to improvements in telegraph exchange systems and particularly to the manner in which motors and printers are controlled .in the operation'of such systems.

In telegraph systems wherein the customers are provided with printing telegraph apparatus,

it is essential or desirable to control the starting and stopping of the motors associatedwith such apparatus. The control of the motors is exercised at a concentration board where the various customers lines terminate.

A customer desiring to send a' message signals the concentration board, whereupon an operator responds to the signal by placing a cord circuit in association with a jack in which the customers line terminates, whereupon the moat the customers station is placed in optor eration. The customer then-operates his printer and sends the message which is recorded upon a printer connected with the cord circuit'associated with hisline.

The printer associatedwith the concentration board is also arranged to transmit a message '-to the printer at the customers station.

The operation of the motor is controlled over the customers line which is provided with a relay and rectifier in such a manner that, when current of one polarity is connected to the line, the relay is energized, and when the current is reversed the relay is de-energized and the motor started to allow the customer to send his message. 9 v i After the message has ,been sent, the operator at the con'centrationboard removes the cord circuit from association with the customers line, which causes the control relay'associated with 'the rectifier to become energized and stop the motor.

Other features of my invention will bedescribed in the description to, follow. 1 My invention is illustrated in the accompanying drawingwherein: v

Fig. 1 shows a customers, station provided witha printer and-control apparatus together with the concentration board; I Fig. .2 shows a modification of the ofFig.1; Fig; 3 shows the construction of the rectifierand-control relay. 1 c

Referring to Fig.4, the customers station is 7 provided witha signal key 1, printer keyboard contacts ;2,-printer magnet 3, motor 8, rectifier cord circuit 5 4 and control relay 5 bridged across the rectifier.

The customers station line is extended to a' signal relaylOO thr bracket at '71.

which is pivotedto the extension 63 of the ward;

Thecustomer;

: mentarily which remove opening the circuit extending-in-serie's through the winding of 'relay 5 andwinding 14' signal relay 100. 1

relay becoming de-energized the" signal lamp 19 through the 'jack, contacts operating when the key; 7 its momentary operation.

a-corporation of New May 21, 1931. Serial No. 538,981 8 Claims. (o1.1'1s'- 4.1)

' ough contacts of aij at the concentratiomboard. v i.

'The cord circuit terminating i'nthe plug. 102

is provided with a line relay 103; a sleeve relay 24 and releaserelay 35."- Associated with. the

cord circuit'is a-printer magnet 36,.motor 37, "and keyboard contacts 39.

The cord'circuit'ot Fig. :2 issimilar equipment and is equipped'with a bat tery reversing switch'48r 'The difference in op eration of this circuit willb'e described later..-.;

Referring to'Fig. 3', the rectifier comprises a numberof copper discs 13, coated on one side with copper-oxide and separated by. :lead washers, bolted together by meansof the nuts 5Q- -51 and the bolt 52 and mounted upon abracket 60. This bracket is fastened by means of the-bo1ts'62." l r v .The'core of control relay coil5 islfastened to the exte'nsionf72 of the bracket .60iby the rivet or screwI'73. 'The armature '10 ispivoted to the The extension 6910f .the armature engages theprojection 68' on the base 65 to a support 61 bracket at 641 The 'base 65 is provided with two clamps 66 and fi'lwhichgrip the glasscase 76Which' contains mercury forclosing contacts fiwhen that'end'of the case '76v is tilted down.-

I 'A tension spring "75 extendsfrom the-lower 7 part of armature '70 tofthearmflSlto hold the armature and theglas's container inxthe, position shown.' I p m p When the armature 70 is attracted toward the core 74 the extension 69- forces the right. end

"of: base" 65 downward and tilts the container 76 sothat the-mercury opens contacts 6.

i 'Iheoperation of the system shown in Fig. )1

is as followsz! or. subscriber desiring to send .95

a .mes'sage operates1-thef signal1ing key :1 fmos ground'from. his line '1 entration board, "thus extending to the cone o the .1 00

The signal closes contacts'l'l and completes the circuit'of,

The. operator at the concentration board, ob-

serving the lighting offlarnp lat-places the plug provided witha ing' the separation of contacts 18 and 20. The

102 of the cord'circuit into the jack 101 causseparation of contacts 18 opensthe-circuit of the lamp 19, while 20 disconnects winding 14 of the signal relay 100 from the line extending to the: customersfistati'on. The signal relay is 7 now held energized by the followingpathz bat tery '80, winding 16, sleeve 12 or" the jack 101,-

sleeve 23 of the plug 102, winding of relay'24 to ground.

Relay24 operating, closes the circuits: otythe supervisory signal 29 in series with the guard lamp 30," as ,follows: battery 90; switch ,7 38' (which is normally closed), contacts 25, lamps 29 and 30, contacts 31 and 32 of relay 35 to ground.

Positivebattery 90 is connectedto theWinding 41 of line relay 103, as follows: battery 90, switch 33, contacts 25, resistance 42 and wind-' ing 41'to, groundi; Positive battery 90'is also connected to the printer mag-netfi at the customerfs station asqf0llows:,90,; keyboard con ,tacts 39', 40, 22,. 21, 1-1, rectifier 4,. 3, 2 to ground. Rectifier 4" is so connected that this positivebattery supply permits currentto pass through it.

As rectifier 4 is in shunt with wir ding of relay 5, it in' effect sho rt circuits this relay winding, causing the relay to release andclose its contacts" 6 which complete the circuit ct motor 8.

Positive battery 90 flowing through .WindingPiO of polar relay 103, is greater, in efiect, than that flowing through winding 41. Energizationof winding. 41,.tends to open relay. contacts 46 while energizationqof winding will cause contacts. 46 to close. .,Battery 90, therefore, will extend to printer magnet 36, as follows: 90, 38, 25, 43, 46, 28, 2'7, 36 to ground The customer. now operating his printer keyboard 'contacts 21causes; the. operation of printer magnet 3 and'the line relay 103. The operation of this line relay opens and closes the cir 'cuit of the printer magnet 36." The telegraph operator at the concentration ofiice may also operate the printer keyboard contacts 39,:which 1 20 ,to close and onnect negative battery 80 through winding 14 of the signal rela to the station circuit. i

will likewise cause the operation or the line relay 103, the printer magnet" 36 and printer magnet 3 at, the. customers' station;-

The telegraph operator at the concentration office in order 'to' terminate a call-depresses key 34', which operates locking relay, 35. The

operationof'this relay opens the circuit of lamps 29 and 30.

The operator at the :concentration board noting the extinguishingof lamps 29 withdraws the plug ironi thejackwhich "causes contacts As the current, namiiiegamv battery '80 will not'flow, thrcughj the rectifier 4', it'wji ll instead fiow'throughlwinding or relays whichin oper--,

*ating stops themotor 8.

pf The. withdrawal of the plug from the jack also causes relays 24, 35 and 103,;to become deeri'er'gized; restoring all circuitsto normal-.-

. -Itshould be noted 'that,"=with this circuit,

Iii the" concentration board ."operator should, 3 by mistake; plug up a callingline. to an unoccupied printer positionwherfthe' powerswitch 38' is turned on, 'no' iine current will be supplied *to' [the station line, thusleaving the customers printer inoperative. The rat-imam thelsiiper-1 visory lamp 29 at the concentration board does not light indicates to the concentration board lamp 29 at the concentration board is ex- I operator.

.sleevc relay -24' 'toythe printer magnet 36.

central station. at the subscribers station, a

printer motor'having a powercircuit, a mercury operator that the line has been connected'to a printer having the power switch turned off. I

The circuit shown in Fig. 2 is arranged to give positive supervision, that is,.the supervisory tinguished, when the associated printer; set is either idle or normallyworking, and the lamp lights. only to indicate that some action is required on, the part of the concentration board In this circuit, both negative and positive battery. are supplied to the central ofice printer positioned by, the switch 48.

Whnthe position is occupied by an operator, f

the switch '43 is-- normally turned to the right. This connectspositive battery to the printermotor 37 and through contacts 26 and 27 of the a If the plug is inserted into the jacket of a station line, the sleeve relay 24 will operate andconnect positive battery to the line, startingthe station ,motor. As before, the sleeve relay: 24

connects the printer magnet 36. to the j contacts of the line relay. It also'lights the guard lampBi) at the 'printer'seubut' the supervisory lamp '29'jat the concentration board?.does' not.

light, as its circuit is. open at the contact 53 of relay 35 and also at thepower switch 148.

f As before,'.the 'printer'operator may signal to disconnect, by "momentarily operating the ref lease key 34. V which locks itself, extinguishs the'guard'lamp 3O, and lights thesupervisory-lamp 29. When 1 the plug is withdrawn from the iia'ck at the conccntration board, the sleevefrelay 24 releases,

This operates a lamp relay 35 extinguishing the supervisory lamp 29, releas'ing the lamp relay, and restoring'the circuit to its 7 normal position, .Itshould be'noted that if the customer should operate his keyboard contacts 2'befor'e the" concentration. board operatorhas li supervisory lamp 29 would light, as wellas the 125 guard lamp 30.- If the printer joperator now switches on the power, this will extinguishthe supervisory lamp 29, start her printerrn'otor 37,

and at the same time, reverse theline currentg to start the customers printer: motorS; What'is claimed is: iv v 1. In a control system, a printer associated witha line circuit, a printer motor having a power circuit, a relay, a mercuryswitch adaptede to close said power circuit upon the release of said relay and to open it upon theoperation of said relay, and a, rectifierincluded'insaid line 1 circuit and bridged by said relay, for causing the operation of said relay when'fcurrent"of'onegg.

polarity is connected tosaid -li'ne-circuit and 140 the release of said relay when current of the opposite polarity is connected theretog} 2. In' a printingtelegraphpexchange system, a

subscribers station connected 'by a line to switch adapted to closesaid power circuit upon the releaseof said relay and. to open it upon the operation of saidrelay and a rectifier included}; in said line and bridged by said relay for caus ing the operation of said relay when the direction of current in said line is normal and the release of said relay when the normal direction of current in said line is reversed.

3. In a printing telegraph exchange system, a central station, a subscribers station connected thereto by a closed line terminating in a switchboard at the central station, a printer at said subscribers station, a printer motor adapted to be started in response to a reversal of the normal direction of current in said line, a cord circuit for connecting a central station printer through said switchboard to said line,

means in said cord circuit responsive to said connection for normally reversing the direction of current in said line and for lighting one lamp associated with said switchboard and another associated with said central station printer, and manually operable switching means in said cord circuit for preventing both the reversal of current in said line and the lightingof said lamps upon the operation of said last-mentioned means.

4. In a printing telegraph exchange system, a subscribers station connected to a central station by a closed line terminating in a switchboard at the central station, said subscribers station having a printer and a printer motor adapted to be started in response to a reversal of the normal direction of current in said line, a cord circuit for connecting a central station printer through said switchboard to said line, means in said cord circuit responsive to said connection for reversingthe current in said line and for lighting a lamp associated with the central station printer, and manually operable switching means in the cord circuit for preventing the reversal of current in said lineand for effecting the lighting of the lamp associated with the central station printer and another lamp associated with the switchboard upon the operation of the last-mentioned means.

5. In a printing telegraph exchange system, a central station, a subscribers station connected thereto by a closed line terminating in a switchboard at thecentral station, a printer at the subscribers station, a printer motor adapted to be started in response to a reversal of the normal direction of current in said line, a central station printer remote from said board and. connectable to said line by a cord circuit cooperating with said switchboard, means responsive to said connection for normally re.-

versing the direction of current in said line,

manually operable switching means for preventing said current reversal in response to said connection, and indicating means at said switchboard for indicating when the current in said lineis reversed by the'connection ofsaid printer to said line and when this current reversal fails to take place.

6. In a control system, the combination of I a printer associated with a line circuit, a printer motor having a power circuit, a mercury switch for controlling said power circuit, a relay for controlling said mercury switch, and a rectifier connected in said line circuit and bridged by said relay for'controlling the latter in accordance with the direction of current flow in said line circuit.

7. In a printing telegraph exchange system, the combination of a subscribers station connected to a central station by a line circuit normally in one condition, means under control of the central station for changing the condition of said line circuit, a printer at the subscribers station, a printer motor having a power circuit, a mercury switch for controlling said power circuit, a relay-for controlling said mercury switch, and a rectifier connected in said line circuit and bridged by said relay for controlling the latter in accordance with the condition of said line circuit.

8. In a printing telegraph exchange system, the combination'of a' subscribers station connected to a central station by a line circuit normally in one condition, means for changing the condition of said line circuit, a printer at the subscribers station, a printer motor having said power circuit, a relay for controlling said mercury switch, and a rectifier connected in said line circuit and bridged by said relay for controlling the latter in accordance with the condition of said line circuit.

' GILBERT s. VERNAM.

v a power circuit, a mercury switch for controlling J 

